1. Field of the Invention
This invention relates to novel pyrazoline compounds, a process for production thereof, and an electrophotographic material comprising such a compound.
2. Description of the Prior Art
Numerous organic photoconductive substances including poly-N-vinylcarbazole have been known for use in electrophotographic materials. Photosensitive materials comprising organic photoconductive substances include the following types.
(1) A type in which a charge transfer complex is formed by a combination of an electron donor compound and an electron acceptor compound.
(2) A type in which a dye is added for sensitization.
(3) A type in which a pigment is dispersed in positive holes or electron active matrices as disclosed in U.S. Pat. No. 3,894,868 corresponding to Japanese patent application (OPI) No. 30328/72 (The term "OPI" as used herein refers to a "published unexamined Japanese patent application") (electron transport binder structures), or U.S. Pat. No. 3,870,516 corresponding to Japanese patent application (OPI) No. 18545/72 (method of imaging photoconductor in charge transport binder).
(4) A type in which the function of the photoconductor is separated into an electric charge-generating layer and a charge-transporting layer as disclosed in U.S. Pat. No. 3,837,851 corresponding to Japanese patent application (OPI) No. 105537/74 (photoconductor overcoated with triarylpyrazoline charge transport layer).
(5) Others.
The novel pyrazoline compounds of this invention can be used as a photosensitive material of any of these types, but exhibit the best characteristics when used as a charge-transporting material in a photosensitive material of the type (4) exemplified above.
U.S. Pat. No. 3,180,729 corresponding to Japanese Patent Publication No. 10366/59 (material for electrophotographic reproduction) discloses pyrazoline-type compounds, and the use of pyrazoline compounds as a charge-transporting material is disclosed in U.S. Pat. No. 3,837,851. In these prior publications, the pyrazoline compounds are limited to those in which an aryl group such as a phenyl group or a naphthyl group is located at the 1-position of the pyrazoline.